I am a 67-year-old woman with virtually no biking experience, so please feel free to speak in very basic terms. I picked up a virtually spotless Sun traditional bike, but the back wheel does not roll freely, and makes a loud clunking noise every quarter turn. I loosened the free wheel and confirmed the key. Is there before tightening it back up again. The chain and spokes are fine and there is no back brake with this model. I’ve watched the YouTube assembly video multiple times. and at one point when putting on the back wheels, the assembler mentioned not overtightening or it could crush the bearings. I am wondering if that is what has happened? I suppose I won’t know until I get a replacement hub with bearings, but I am open to trying any and all suggestions you may have have. Thank you so very much!

It could definitely be a binding bearing. Another potential cause is the freewheel itself. Often a lower quality freewheel will have slip in it, making a “clunk-clunk-clunk” when pedaling. Is the sound happening only when pedaling, or when coasting as well? By your description (every 1/4 turn of the wheel) it sounds more likely to be a bearing.

IIRC these trikes have one drive wheel and one that spins free.

So, start by localizing the proem to oneorthe other. Tilt the trike and spin each wheel off the ground.

If the noise comes front the non-drive wheel, it's likely a bearing.

OTOH if, as I suspect, it comes from the drive side, it's more complicated, and you'll need to work through possibilities.

The bike is off the ground, and when attempting to spin the back right wheel, without moving the petals, the clunking continues. It is definitely on the back right side, and when holding onto the frame area in the back, you can feel the clunking. It’s not just a noise.

I hope that helps, as I’m not sure how successful I’ll be in fixing this myself. My hands just aren’t very strong. Thank you all so much.

OK, so it's the drive side, which opens up possibilities.

Next questions are about the drive arrangement.

Is it single speed or multi-gear? If multi-gear, is it deraileur or internal gear hub?

And is there only a single chain running from crank to axle, or two chains, crank to hub & hub to rear axle?

It’s a Miami Sun traditional adult trike, which is single speed. When the wheel is off, and the pedals are turned, there is no noise and the axle spins freely. When the wheel is on, there is a clunking noise and the wheel does not move freely. It moves, but not freely. I just put the wheel back on, but didn’t fasten it, and it seemed to be quiet. When I put the nut on, the clunking started again upon rotation. I loosened the nut, sprayed the parts that I could see pertaining to the wheel with lubricant and rode it a short distance noise. That may just be a fluke, because I know the former owner tried everything when the noise started. He and his wife ride their bikes every day and I picked this up for next to nothing thinking I could fix it. Long story short, someone stole my Schwinn meridian and the bike. I’m currently riding is Rusty and was in the trash. It rides good, so I shouldn’t complain about this beautiful bike. I picked up that doesn’t work. I’ll try and ride again in the morning, which is when I usually go 5 miles through the park. Living in Florida, the heat is-too much. Sorry for my life story

OK so it's pretty much reduced to be about the wheel, axle and the axle's bearings.

I suspect that maybe a part is missing, or that you're simply overtightening the wheel mounting nut.

These have a simple system where the axle slides within the tube and kept in place by a stop on one end and the wheel on the other. It likely requires a bearing, spacer, or washer behind the wheel. It's important that the nut is tightened ONLY enough to take up play and no tighter, lest it jams the assembly.

BTW Sun offers links to owners manuals. Odds are you can download the one for your trike, or a similar model. Find the exploded view and confirm that you have all the parts assembled in the right sequence.

Thank you, that’s what I’m thinking as well. The last donor may have just tightened the nut too much. At first, I thought it was the axle key, but when I loosened things, I was able to find it and I actually cleaned it up before putting it back Now I am playing with the brakes which are extremely loud and squeaky. I had just replaced them on my old Miami sun, so at least I know what I’m doing for that. I wish it wasn’t so hot and windy, or I’d try riding again now, but I’m too old and can’t do it. Stay tuned for my update in the morning and thank you again. I appreciate all of you.

here's the trike...
https://familybicyclelw.com/product/...sun-trike-7sp/

both rear wheels are typically identical, and both have bearings in them... one spins freely, and one hub has holes that one of which mates up to a pin in the axle's flange.

the right side's drive axle "bearings" are inside the Frame tube.. the drive side's wheel hub's bearings are not in play.

synjondra... you need to take the bike to a mechanic and have him or her look it over CAREFULLY, with experienced eyes... the right rear wheel may have been improperly installed, and you might be hurt if it fails, since that right wheel is also the Rear Brakes.

Single-wheel-drive trikes drive the left wheel, so which is the drive side - the one with the chain or the one with the wheel that drives the trike?

When I’m sitting on the bike, it’s the right rear wheel, which is the one that has the free wheel and drives the axle when peddled

I don't believe this is a e-trike, but I any case it's irrelevant. Based on the OP's responses, it seems we were on the same page and they have it sorted now.

My best guess, without examining the trike, is that it is an axle bearing, there are typically 4 (two on the left and 2 on the right). You would need the proper tools for removal and pressing in new ones and if one is bad I would replace all 4. Sometimes not an easy job depending on rust/conditions etc. I have done several of these replacements. I did a search on YouTube for this process but could not locate a video showing the process.

I don't know where e-trike came from, but I found the Miami Sun assembly guide and it's not how I thought it would be.

Small print and old eyes.

Good morning,

Hopefully I haven't caused too much confusion due to my explanation of the situation, which is a loud, clunking noise (which can be felt). This is a Sun Adult Trike; single speed (no rear brake) Traditional model. Looks spotless with little to no rust anywhere. Spokes, chain, freewheel, axle key all appear to be found. The issue is:

1. Intermittent
2. With bike off the ground, happens with rear right drive wheel on or off
3. Occurs (again intermittent) when pedal is rotated forward (not back)
4. Occurs when coasting - I've ridden the bike a couple of times; once with no noise or issue. Next time after a smooth start, the loud clunking and reverberating could be felt in the rear and lasted several rotations before stopping.

I agree with Joe that it's the axle bearings, which doesn't seem to be something I could fix. I don't have the proper tools or hand strength. This is also something that's too expensive for me to have repaired, given my fixed income.

I appreciate all of your responses.

Thank you.

I just went through diagnosing and fixing the clunking on my wife's Sun trike. It's the 7 speed model, but the chassis, axles, bearings and wheels are all common between all of the versions.
First, both of the wheels have 3 holes which line up to prongs on the axles, these are what pull the right side hub when pedaling. Both hubs are identical, as well as symmetrical, so you can flip the drive-side wheel so what was the outside of the hub is now on the inside and interfacing with the 3 prongs on the axle. The reason I mention this is that those holes in the hubs get ovalized as you ride and start to clunk around, especially on turns. You can try flipping the drive side or the rear wheels altogether.
After that, the axle bearings are a major culprit. The bearings that the Sun trikes ship with are not sealed cartridges, so they can and do allow moisture to get in and play havoc. There are 4 bearings in the rear axle tube, 2 on the drive side, and 2 on the non-drive side. Removing the axle is an unholy PITA, requiring a lot of PB Blaster, a long punch (or piece of rebar), and a good heavy mallet or deadblow hammer. Profanity helps as well. The operation of actually replacing them isn't complicated, it's just annoying, dirty, and labor intensive. I used sealed NSK 6202 bearings and replaced all 8 of them on the bike, 4 for the axle, 2 per rear wheel. If you do this operation, or have someone do it for you, replace the freewheel while you're at it. One note of caution, be ready to either toss the trike or buy a new axle. That axle tube is completely sealed, but not absolutely watertight. There is the possibility that the bearing flats on the axle are rusted too badly to sit in the bearing then it's time to replace or scrap. Feel free to PM me about this, since I just did this operation and remember it well.
Phil

I don’t know how to send a message as a pop-up appears talking about messaging only if there are less than 10 posts.

I have a rusted out Miami Sun trike (pulled out of curbside trash) that rides like butter, and I suppose I could swap the rear. Will probably have to enlist someone else though, since my hands are very weak and painful with arthritis.

thank you again, and feel free to PM me since I can’t seem to reach you.

That's an anti-spam feature of the forum, along with not being able to post pictures or 5 post/day until you have 10. Once you have 10 you can message and post pictures.

You CAN download pictures to your album and others can see them before then.

Tell me about it - my near vision isn't good enough to read this and I've broken all my glasses, so I'm getting by with bodged repairs until I get a new prescription next week.

If the clunking is due to bad bearings in the through axle on my Sun Traditional Trike, would the noise be constant or intermittent? It seems if something is bad, it would stay bad and not “heal itself” periodically. I can ride the bike a couple of blocks before returning home without having any noise but then the next time I ride, it could start up for several rotations and then stop again. It’s not the drive wheel hub, since it can happen when I’m just testing the axle with no wheel attached

I hate to ask this for fear of jinxing something, but I had wanted to see initially if the left non-drive wheel nut was tightened too much. Unfortunately, I was too weak to loosen it. I just mustard up Herculean strength though, and was able to loosen the left nut (right drive wheel nut is already a smidge loose), and I went for a ride. My driveway is an angle with bricks, so already bumpy and I went down one block before turning around and heading back. I went past my house and up a couple more bumpy areas turned around and came home up my bumpy driveway…there was no noise on the entire trip. Could it be that simple?? Of course my brakes squeal like a son of a gun and I’m gonna have to address that, but right now I’d be happy if I could just ride straight without clunking and being jolted. What do you think?

Yes, it actually is that simple.

The axle lacks thrust bearings at each end, and relies on washers for that purpose. That's why the instructions warn about over tightening it.

From my earlier post------
These have a simple system where the axle slides within the tube and is kept in place by a stop on one end and the wheel on the other. It likely requires a bearing, spacer, or washer behind the wheel. It's important that the nut is tightened ONLY enough to take up play and no tighter, lest it jams the assembly.


Note that the other end usually has bearings in the wheel, so it can be tightened fully.

Re: Brake squeal... set the pads so that the LEADING EDGE touches the rim before the Back edge of the pad... The Leading Edge is the part of the b=pad that touches the rim first AS THE WHEEL SPINS like when you're riding the bike... so it's the REAR of the pad when you're sitting on the bike.

i use a flat toothpick to set the pads... if you don't have any, improvise...

and if your bike has those terrible band brakes in the rear, and that's what's squealing...... good luck... i've used a handful of clay based dirt tossed into them, and a start-stop-start-stop(repeat) test ride to make them quieter... they are typically marginal at stopping a bike anyway.,, the front sidepull brakes are usually worlds better...

If you have DISC brakes, then there are numerous threads on this forum... run a search for "Squealing Disc Brakes"